Lung Ultrasound Scores Progress Differently in Extreme and Very Preterm Infants after Birth: A Multicentre Prospective Study.

Introduction: The lung ultrasound score (LUS) has been suggested to predict moderate-severe bronchopulmonary dysplasia (msBPD) in preterm infants. We aimed to assess LUS evolution after birth in preterm infants and the effect of gestational age.

Methods: This multicentre prospective observational study was performed with newborns born before 33 weeks of gestation. We created two groups: group 1 (23-27 weeks) and group 2 (28-32 weeks). We compared LUSs between the groups from birth until 36 weeks of postmenstrual age, and we estimated the LUS evolution in each group with a linear multilevel mixed-effects regression model. The effects of the need for surfactant or an msBPD diagnosis were also studied.

Results: We included 339 patients: 122 (36%) in group 1 and 217 (64%) in group 2. The infants in group 1 showed a steady progression in the LUS from birth until 4 weeks of age and a subsequent decrease; the infants in group 2 showed a progressive decrease in the LUS throughout the study. This progression varied significantly in the first weeks of life in infants who required surfactant at birth and after the first week of life in the patients diagnosed with msBPD.

Discussion/conclusions: Extremely preterm infants showed persistently high LUSs during the first weeks of life, regardless of the progression to msBPD. In this group, the infants who did not require surfactant at birth exhibited an increase in their LUSs after the first week until their values were equal to the remaining infants in their group.